Green H2 is considered a sustainable energy carrier, but its volatility makes it difficult to transport and store. A promising alternative for H2 storage is liquid organic hydrogen carriers (LOHCs), in which hydrogen is covalently bound and later extracted through catalytic cycles. LOHCs are compatible with current fuel infrastructure [1], and some LOHC systems, including the methylcyclohexane/toluene (C7H14/C7H8) pair, have already been commercialized [2]. However, catalyst performance during the loading and unloading of LOHCs must be improved to ensure economic viability. Pt catalyzes the dehydrogenation of C7H14 but also promotes unwanted C-C bond cleavage reactions [3], such as the demethylation of C7H8, which destroys the organic carrier. C-C bond cleavage is known to occur mainly at low-coordinated sites [4]. It has been suggested that these sites can be blocked by S-decoration and that undesired side reactions therefore can be prevented by modifying the catalyst surface with S [5]. Nevertheless, the effects of S-modification on the dehydrogenation and demethylation mechanisms of C7H14 have not been investigated. The purpose of this project is to quantify the influence of S and other dopants, as well as of low coordnated sites, on LOHC-relevant reactions, with the goal of identifying feasible strategies for catalyst optimization. (1) Preuster, P.; Papp, C.; Wasserscheid, P. Acc. Chem. Res. 2017, 50, 74–85. (2) Okada Y.; Mikuriya, T. Y. Kemikaru Enjiniyaringu 2015, 60, 187–193. (3) Okada, Y. et. al. Int. J. Hydrog. Energy 2006, 31, 1348–1356. (4) Somorjai, G. A.; Blakely, D. W. Nature 1975, 258, 580–583. (5) Auer, F, et. al., P. Catal. Sci. Technol. 2019, 9, 3537–3547.